Chlorination



Dec. 8, 1931'.

E. E'. AYRES, J'R

CHLORINATION Filed Feb. 4. 1927 Patented Dea-s, 1931- UNITED STATES 1 .1.Ti:.NT OFFICE i' 'EUGENE E. AYIms, or swAn'rimoItE, PENNSYLVANIA.`'assIeNoIa ro 'rim B. A. s.

. COMPANY, or PHILADELPHIA, PENNSYLVANIA, A coI'onA'rIoN 0I' DnLAwAImcIILoRINA'rIoN Application led February 4, 1927. Serial No. 165,874.

My invention relates tochlorination and partlcularly to the chlorinationof aliphatic hydrocarbons by substitution with the formation of hydrogenchloride, and my invention4 5' includes a dehydrating step particularlyapplicable in chlorination in accordance with my invention and alsogenerally applicable. In chlorination of aliphatic hydrocarbons bysubstitution, hydrogen chloride is produced in the chlorinatingreaction, and water in the equipment used in chlorination causes theformation of hydrochloric acid. I have found that it is essential tosuccessful commercial chlorination by substitution, not only '15 toguard against leakage of water into the 'equipment usedin suchchlorination but to prevent introduction into the system of sub#stantially all moisture that will not remain in vapor phase: at alltimes in the chlorinat# ing apparatus under the various conditionsexisting therein. I have found that aliphatic hydrocarbons in liquidform, particularly uantities thereof recovered from products of t echlorination step and from which hydrod gen chloride has been removed byabsorption with Water as Well as fresh supplies of such hydrocarbons,contain so much Vmoisture which will not settle out that chlorinationthereof by substitutionis not commercially practicable because of thepractical diiiiculty of preventing the harmful eifects of the relativelvlarge quantity of hydrochloric acid that is produced in and destroys thechlorinating equipment. I have discovered that such chlorination ofsuchhydrocarbons 'is commercially practicable if all such hydrocarbons, bothsuch quantities'as maybe recovered from the products of chlorination andfreshsupplies to the system, are substanformation of hydrochloric acidunder any of the various conditions existing in theY tially freed of allmoisture that will cause drogen chloride of such hydrocarbons containingwater that-Will not settleout results in precipitation of moisture inthe form of v aqueous hydrochloric acid, and that when the precipitatedmoisture is removed the hydrocarbons are so far freed ofwaterthatchlorination thereof by substitution is'commercially practicable becausethey contain no moisture that will be precipitated in the chlorinatingapparatus; and traces of water are'removed that 'cannot be'removed bycalcium chlorideor solid sodium hydroxide.

Dehydration of aliphatic hydrocarbons in accordance with my invention isalso more effective than dehydration thereof by sulphuric acid and othersubstances that are not soluble in the hydrocarbons because hydro enchloride dissolves in the hydrocarbons and is therefore certainlybrought into effective relation withall moisture therein and itdissolves in the moisture, formin aqueous hydrochloric acid in particleso such ma iture that the Will settle by gravity. ut, sulphuric aci mustbe brought mechanically into contact with the moisture which is widelydisseminated inthe hydrocarbon and even, the formation of an emulsion ofthe sulphuric acid and h drocarbon does not certainly bring that ac1dinto effective relation with the dispersed moisture, and, if it does,the operation is an absorption of the moisture by the acid. Furthermoresulphuric acid oXidizes andpolymerizes the hydrocarbons and leavesobjectionable impurities and traces of,

sulphuric acid and sulphur dioxide therein, S5-

and it is, therefore, hi hly objectionable as an agent for dehydrationof substances for general purposes and particularlyin 'preparation forchlorination.' 1

Moreover, the presence of dry hydrogen 90 chloride in a hydrocarbondehydrated in ac cordance vwith my invention isnot a disadvantage inchlorination' and if a neutral dehydrated oil is desired thehydrogenchloride may be removed by mere distillation in the case of higherboiling oils, and by rectification in the case of lower .boiling oils. f

The avoidance of diculties' in chlorination. dueto the presence offormation of tent that precipitation of moisture in the sysf practice ofmy invention, even though hydrogen chloride is formed in thechlorination,

ecause the substances that contain moisture and are to be introducedinto or returned to the chlorination reaction are preliminarilysubjected, in acid resistin apparatus, to the same influences that woulotherwise, because of that moisture, tend to precipitate aqueoushydrochloric acid at sensitive parts of the equipment. In other Words,dehydration of a hydrocarbon by acidulation'with hydrogen chloride makesthe hydrocarbons dryer than any previously known method of dehydrationsince previously known methods'leave moisture in the hydrocarbons thatis preci itated in systems for the chlorination t ereof, whereasdehydration by hydrogen chloride acidulation removes moisture to such anextern will not occur by reason of the presence of hydrogen chloridetherein.

Dehydration is particularly important if the substance being chlorinatedproduces with water a constant boiling mixture that is so low in watercontent that traces of moisture are not carried thru the system in vaporphase but are deposited in liquid phase and absorb hydrogen chloride.For example, pentae forms with water a constant'boiling mixture of verylow water content' while benzol will carry along a greater quantity ofmoisture because it forms with water a constant boiling mixture ofgreater water content.7

In the practice of my invention the precipitated aqueous hydrochloricacid will completely settle out of the oil by gravity butithevsettlingis vmuch more rapid if the particles tus whereby chlorinationof certain are agglomerated, as by passing the oil over or through anysubstance or apparatus suitable for that purpose. A 4

Hydrogen chloride produced in chlorination may be removed from the otherproducts of the chlorinating reaction by absorption in water, butifvunchlorinated hydrocarbons are contained in those` products and areso freed of acid, those hydrocarbons are then moisture laden and carrymoisture into the equipment if they arefrreturned directly to thechlorinating reactjiof, and fresh su plies of hydrocarbons are moistureladen. ut, chlorination in accordance with my invention ensures thatsuch undesirable moisture will not be introduced int-o the chlorinatingequipment.

In order to assist in the understanding of my invention but withoutlimiting my invention thereto, I will describe my chlorinating rocess,including dehydration of hydrocarons, in connection wlth one form ofapparatus suitable to the practice thereof. To that end there isdiagrammaticallyV shown in the single figure of the annexed drawing, apray roc'arbons of the aliphatic series, may be carried out inaccordance-with my invention, it

being specifically understood that modifications and variations in theconstruction shown may be made for the purpose of applying my 15 to thereacting cham er 17 of the chlorinati-ng operation, the chlorine beingintroduced into pipe 15 by pipe-16.

The mixture of chlorine and the substance to be chlorinated passes intoreacting chamber 17v where the. reaction may be effected in any desiredmanner.- The products of the reaction pass through pipe 18 and cooler 18to a rectifying column 19 in which a reflux is maintained withhydrocarbon passed through pipe 50 fromcirculating tank 12, and fromwhich the chlorinated product is withdrawn in .liquid form, togetherwith some unchlorinated hydrocarbon, through pipe 20, and from whichuncondensed vapors are passed to condenser 21 by pipe 20a. Hydrocarbonscondensed in condenser 21 and which are to be returned to thechlorinating reaction pass through pipe 22 to circulating tank 12 andthe vapors from condenser 21 pass through pipe 23 to the hydrochloricacid absorber 24 wherein the temperature is controlled by cooling waterfrom pipe 240. Water is introduced to the absorber 24 through pipe 24aand aqueous hydrochloric acid passes from the absorber 24 through pipe.25. Vapor from absorber 24 passes through pipe 26v to'neutralizer 27that is supplied with aqueous caustic soda by pipe 27?) and drained bpipe 270. Vapors pass from neutralizer 27 Vthrough pipe 1a to condenser29 from which liquid passes to decanter 30 and there water is drainedthrough pipe 31 While hydrocarbons pass through pipes 1b and 1 toacidulator 3. Fresh supplies of hydrocarbons to be chlorinated areled toacidulator 3 through pipes-2 and 1, and acidulated hydrocarbons passfrom acidulator 3 through pipe 4 to any suitable settling) device 5wherein settling may be hastened y ag lomerating means. A compressor 37may e interposed in pipe 1a if desired. The acidulating chamber 3consists of any suitable container having within it any construction,such as raschig rings 3a, that will facilitate contact between thesubstance to be acidulated and the hydrogen chloride.

Hydrogen chloride is brought v.into the acidulator preferably. at thebottom .thereof by pipe 7 and any excess hydrogen chloride is withdrawnfrom the upper portion of the acidulator by pipe 8. Any source ofhydrogen chloride may be used but in chlorination of the type describedit is conveniegt to use V'the uncondensed cooled vapors from thechlorinating reaction, preferably'after removal therefrom of chlorinatedsubstances yproduced inthe chlorinating reaction.

The supply of hydrogen chloride to the aci'dulator 3 may be drawn fromthe products passingtothe hydrochloric acid absorbu s er, as by pipe 7leading from pipe 23 at a point on the high ressure side of pressurereducing valve 28 herein, and are returned to those products by pipe 8leading to a point Y in pipe 23 on the low pressure side of valve v28 ifthe @emulation is 'carried on when the. substance to be dehydrated is invapor phase,

precipitation of the contained moisture will occur upon condensation ofthe-substance.

Although the precipitated: moisture will separate out by gravity, thatseparation is ac celerated when the 'aqueous hydrochloric acid particlesare agglomerated and such agglom-4 eration may be veffected by passingthe hydrocarbon, containing the precipitated moisture, over coke breeze5a, present in the a glomerator 5. TheV coke breeze is preferab ysupported onf. perforated partition 9 leaving a settling chamberlO fromthe bottom of which acid is withdrawn and 'from annpp'er level of whichthe dehydrated hydrocarbon is withdrawn through pipe 11to circulatingtank 12.1.

While dehydration in accordance with my i invention is particularlyadvantageous in chlorination in accordance with my invention, it isgeneraly applicabl'eto dehydraation of hydrocarbons lmmiscible withwater as in electrica] equipment.

the dehydration of oils u sed for immersion of While I have describednumerous details [for-thepurpose of assisting in the understanding of myinvention, it is not limited thereto butinclndes such modifications andI' variations as fall within the hereunto a`.

nded claims. In this connection, itv will apparent from the foregoingthat I have described a rocess and apparatusvsuitablc 5to the practicethereof, whereby important -advantages'are attained in the chlorination'of various substances, including chlorination of pentanes. Thus, in thepractice of my invention introduction of moisture into the such returnof chlorinated products thereby equipment is substantially minimized.'4And,

substances that are containedin the products of chlorination and arereturned to the chlorination `step `are repared for such return byremoving c lorinated substance, thereby cplreventi formationof'undesired higher orides t at 'would be formed by lproviding Va dryvapor mixture conydrogen chloride and free of chlosubstances'and'snitable for use in tainin rlnat subsequent dehydration ofsubstances passing to the chlorinating step. And, unchlorinatedsubstance that lis contained inV the chlorides and and also` products ofchlorination and is to be returned Y to thechlorinating reaction iswithdrawn so far as practicablypossible from thehydrogen chloride thatis subsequently absorbed with water, thereb vavoiding contaminationchloride removal.A And, such unchlorinated substance asis not withdrawnfrom the hydroglen chloride and becomes moisture laden of such substancey Water in the hydrogen substance and keeps dryunchlorinated substancethat is returned to the chlorinating operation.

Still referring to the chlorination of pen? I tanes as an exemplaryapplication of myinthereof as follows: Vapor of pentanes formed at C. to100'C. and at about 75 pounds gauge pressure and chlorine vapor at`\40C. to 60 C.

vention, I have carried out the chlorination l and at a pressure above60 pounds, have been l brought together in the proportion of 15 to 20parts pentane to one part chlorine, at about a' .85 C. to 100 C. under apressure of 35 to '50 pounds and caused to react by heating to atemperature between 275 C. and 325 C. Then .the :products ofchlorination .were cooled to about 80 C. to 85 C. under a preslsure of15 to 25 vpounds and introduced into a rectifier from which a mixture ofamyl ntanes was withdrawn in liquid form jwlnle a reflux of pentanes atatmospheric temperature 'was maintained. The vapors leaving therectifier were at the -boilmg point of pentane at the pressure used andwere condensed under afpressure that would cause the pentanes to liquifyat the temperature of cooling water avallable, for exam-- ple 10 unda,Hydrdgen chloride was absorbed `y waterk under atmospheric pressure atatem rature'in the neigh rhood of 40 C. Congnsation and dehydrationv ofacidfreed pentane was conveniently carried out under labout 10 poundspressure, that pressure bein maintained in the circulating tank. What'ters Patent is:

1 .v In the chlorination of hydrocarbons the process comprisin 'reactinga hydrocarbon with chlorine,wit drawingchlorinated hyclaim and desire tosecure by Let*- drocarbonV and unchlorinated. hydrocarbon 'i from thereaction products, contacting the remaining products with 'water toremove hydrogen chloride therefrom, contacting products paing from saidwater contact with products passing from the reaction, removing waterprecipitatedv by said 12st vmentioned contacting step, and passing thedehydrated product to said reaction.

2. In the chlorination of hydrocarbons the process comprising reacting ahydrocarbon with chlorine, withdrawing chlorinated hydrocarbon from thereaction products, and

, contacting dry remaining products containing hydrogen chloride withfresh'quantities of hydrocarbon passing to the reaction and therebydehydrating the fresh hydrocarbon.

3. In the chlorination of hydrocarbons, the process comprising reactinga hydrocarbon With chlorine, withdrawing chlorinated hydrocarbon fromthe reaction products, contacting with Water a portion of the reactionproducts containing hydrogen chloride and thereby removinghydrogenchloride therefrom, contacting products passing from said Water contactand fresh hydrocarbon with another portion of said reaction productscontaining hydrogen chloride, removing from the mixed hydrocarbonswater' precipitated by said last mentioned contacting step, and passingthe moisture-freed product to the ehlorinating reaction.

4. In the chlorination of hydrocarbons, the process comprising passing ahydrocarbon and chlorine through a reaction zone and thereby reactingthe hydrocarbon with the chlorine, withdrawing chlorinatedhydrocarbonfrom the products wliiclrpass from the reaction zone, contacting withwater the vapors which pass from the reaction zone and Which containhydrogen chloride and from which chlorinated hydrocarbon has beenWithdrawn and thereby removing hydrogen chloride from said vapors,contacting fresh hydrocarbon and products which pass in vapor phase fromsaid water-contacting step and which contain unchlorinated hydrocarbonand moisture with vapors which pass from the reaction zone and fromwhich chlorinated hydrocarbon has been Withdrawn and which containhydrogen chloride, removing from the mixed hydrocarbonsv the aqueousprecipitate formed therein by said last-mentioned contacting step, andpassing to the reaction zone the water-freed product.

'5. In the chlorination of hydrocarbons, the process comprising passinga hydrocarbon and chlorine through a reaction zone and thereby reactingthe hydrocarbon with the chlorine, contacting with water vapors whichpass from said reaction zone and which contain hydrogen chloride andthereby removing hydrogen chloride from said vapors, contacting thevapors which pass from said Waterl contacting step and which containunchlorinated hydrocarbon and moisture with a basic neutralizing agentand thereby neutralizing the acidity thereof, contacting theunchlorinated hydrocarbon passing from said neutralizing step withvapors which pass from the reaction zone and which contain hydrogenchloride. removing from the hydrocarbon passing from said last-mentionedcontacting step the aqueous precipitate formed by said last-mentionedcontacting step, and passing to the reaction zone the water-freedhydrocarbon. n

6. In the chlorination of hydrocarbons, the process comprising passing ahydrocarbon and chlorine through a reaction zone and thereby reactingthe hydrocarbon with the chlorine, contacting with water vapors whichpass from said reaction zone and which contain hydrogen chloride andthereby removing hydrogen chloride from said va ors, contacting theproducts which pass rom said water-contacting step and which containunchlorinated hydrocarbon and moisture with vapors which pass from thereaction zone and contain hydrogen chloride, removing from thehydrocarbon'passing from said last-mentioned contacting step the aqueousprecipitate formed by said last-mentioned contacting step, and passingto the reaction zone the Water-freed hydrocarbon.

7. In the chlorination of hydrocarbons, the process comprising passingthrough a reaction zone in vapor-phase a h'ydrocarban and chlorine andthereby' reacting the hydrocarbon with the chlorine, by rectificationwithdrawing chlorinated hydrocarbon from the remaining products whichpass in vaporphase from the reaction zone, contacting with water thevapors which pass from the reaction zone and which contain hydrogenchloride and from which chlorinated hydrocarbon has been withdrawn andthereby removing hydrogen chloride from such vapors, contacting with abasic neutralizing agent the vapors passing from said water-contactingstep and thereby neutralizing the acidity thereof, condensing fromthevapors which pass from the water-contacting step unchlorinatedhydrocarbon containing water, contacting the condensed unchlorinatedhydrocarbon with vapors which pass from said reaction zone and whichcontain hydrogen chloride and from which chlorinated hydrocarbon hasbeen withdrawnfpassing residual vapors from said last-mentionedcontacting stgp to said Water-contacting step, removing rom thecondensed hydrocarbon the aqueous precipitateformed therein by saidvapor-contacting step, and passing to the reaction zone in vapor phasethe water-freed hyd1'"oca1bon.

8. In the chlorination lof hydrocarbons, the process comprising passingthrough a reaction zonein vapor-Phasen hydrocarbon and chlorine andthereby reacting the hydrocarbon with the chlorine, contacting withwater vapors which pass from thoreaction zone and which contain hydrogenchloride and thereby removing hydrogen chlorideI from such vapors,contactingwith a basic neutralizing agent the vapors passing from saidwater-contacting step and thereby neutralizing the acidity thereof,condensing naaimac-v from the vaporsiwhichl pass from the water-Vcontacting step unchlorinated hydrocarbon containing water, contactingthe condensed imchlorinated hydrocarbon with vapors wbich- VpassY fromsaid reaction zone Vand Ywhich contain hydrogen chloride, passingresidual froml said last-mentioned Y contactingstep to saidwater-contacting step, removing from the condensed hydrocarbon 10theaqueousv precipitate formed therein by said vapor-contacting step,and .passing to the reaction zone in vapor-phase the Waterfreehydrocarbon.

9. In the chlorination of hydrocarbons, the process comprising passingthrough a re- 'action zone in vapor-phase a hydrocarbon and chlorineandthereby reacting the hydrocarbonand chlorine and thereby reacting'thehydrocarbon with the chlorine, contacting 20 with water vapors whichpass from the reaction zone and which contain hydrogen chloride andthereby removing hydrogen chloride from such vapors, condensingunchlorinated hydrocarbon containing mois# 25' ture from thel productspassing from said .water-contacting step, contacting the con"-1 densedunchlorinated hydrocarbon with vapors passing fromsaid reaction zoneand. containing hydrogen chloride', passing residualvapors rom'saidlast-mentioned contacting"A step to said water-contacting step, removingfromthe condensed hydrocarbon aqueous precipitate formed therein bysaidcontact thereof with said vapors, and passlng to the reaction zonein vapor-phase the Waterfreed hydrocarbon.

Y 10. In the chlorination of hydrocarbons, the process comprisingvpassing a hydrocarbon and chlorine' through a. reaction zone andthereby reacting the hydrocarbon with the. chlorine, condensing from theproducts which pass from the reaction zone a part of the unchlorinatedhydrocarbon in said prode' ucts, contacting with-water vapors which passfrom the reaction zone and which conl tam hydrogen chloride and residualunchlovrlnatedv hydrocarbon and thereby removing hydrogen chloride fromsaid substances, contactlng products vwhich pass from said4 5i.water-contac step and which contain un- Y I chlormatedhy rocarbon andmoisture `with vapors which pass from the reaction zone and whichcontain hydrogen chloride, removlng from the hydrocarbon passing fromsaid Y 55.1,ast-mentioned contacting-step the aqueous i xprecipitateformed therein by said last-mentioned contacting-step, and assing to thereaction zone the condensed hypdrocarbon and o fthe'vvater-freedhydrocarbon. 9 testimony whereof,` I have signed my namotpthisification. y UGENE E. AYRES, JR.

CERTIFICATE 0E CORRECTION.

Parent No. 1,835,202. I Granted December s, 1931, w

EUGENE E. AYREs, JR.

l It is hereby certified that error appears in the printedspecificationof the above numbered patent requiring correction asfollows: Page 1, line 73, for the syllable "ture" read tude; page 3,line 35, for the misspelled word "generaly" 'read generally; page 4,line 91, claim 7, for the misspelled word "hydrocarban" readhydrocarbon; page 5, lines 18 and 19, claim 9, strikel out the-'words"and chlorine and thereby reacting the hydrocarbon"; and that the saidLetters Patent should be read with these corrections therein ,that thesame may conform to the `record of the case in the Patent Office.

Signed and sealed this 9th day oi February, A; D. 1932.

l M. J. Moore. v (Seal) Acting Commissioner of Patente.

